Field of the Invention
The present invention relates to an image processing device and an image processing method of processing polarization tomographic images of a subject eye.
Description of the Related Art
Optical coherence tomography (Optical Coherence Tomography: hereinafter, OCT) utilizing multiple-wavelength optical-wave interference is capable of obtaining tomographic images of a sample (particularly, eye fundus) at high resolution.
Recently, with an ophthalmic OCT device, there have been attempts to acquire functional OCT images which image optical characteristics, movement, etc. of eye-fundus tissues in addition to normal OCT images which image the shapes of the eye-fundus tissues.
Polarization OCT which is one of functional OCT carries out imaging by using polarization parameters, which are one of the optical characteristics of the eye-fundus tissues.
The polarization OCT is capable of forming polarization OCT images and carrying out discrimination and segmentation of eye-fundus tissues by utilizing the polarization parameters. The polarization OCT uses the light modulated to circularly polarized light as the measurement light to observe a sample, detects interference light divided as two orthogonal linearly polarized light, and generates a polarization OCT image (see International Publication No. 2010/122118).
In Invest Ophthalmol Vis Sci. 2013 Jan. 7, Zotter, S., et al. “Measuring retinal nerve fiber layer birefiringence, retardation, and thickness using wide-field, high-speed polarization sensitive spectraldomain OCT”, Retardation (phase retardation) and Birefringence (birefringence) obtained from the polarization OCT are obtained. In this case, the birefringence is obtained from a Retardation value in RNFL extracted from Intensity (luminance) image and the thickness of RNFL. Note that, in the polarization OCT image, polarization parameters (Intensity, Retardation, Axis Orientation (fast-axis orientation), DOPU (polarization degree), etc.) are imaged.